#
# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements. See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership. The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License. You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied. See the License for the
# specific language governing permissions and limitations
# under the License.
#

import errno
import os
import socket
import sys

from TTransport import *


class TSocketBase(TTransportBase):
  def _resolveAddr(self):
    if self._unix_socket is not None:
      return [(socket.AF_UNIX, socket.SOCK_STREAM, None, None,
               self._unix_socket)]
    else:
      return socket.getaddrinfo(self.host,
                                self.port,
                                socket.AF_UNSPEC,
                                socket.SOCK_STREAM,
                                0,
                                socket.AI_PASSIVE | socket.AI_ADDRCONFIG)

  def close(self):
    if self.handle:
      self.handle.close()
      self.handle = None


class TSocket(TSocketBase):
  """Socket implementation of TTransport base."""

  def __init__(self, host='localhost', port=9090, unix_socket=None):
    """Initialize a TSocket

    @param host(str)  The host to connect to.
    @param port(int)  The (TCP) port to connect to.
    @param unix_socket(str)  The filename of a unix socket to connect to.
                             (host and port will be ignored.)
    """
    self.host = host
    self.port = port
    self.handle = None
    self._unix_socket = unix_socket
    self._timeout = None

  def setHandle(self, h):
    self.handle = h

  def isOpen(self):
    return self.handle is not None

  def setTimeout(self, ms):
    if ms is None:
      self._timeout = None
    else:
      self._timeout = ms / 1000.0

    if self.handle is not None:
      self.handle.settimeout(self._timeout)

  def open(self):
    try:
      res0 = self._resolveAddr()
      for res in res0:
        self.handle = socket.socket(res[0], res[1])
        self.handle.settimeout(self._timeout)
        try:
          self.handle.connect(res[4])
        except socket.error, e:
          if res is not res0[-1]:
            continue
          else:
            raise e
        break
    except socket.error, e:
      if self._unix_socket:
        message = 'Could not connect to socket %s' % self._unix_socket
      else:
        message = 'Could not connect to %s:%d' % (self.host, self.port)
      raise TTransportException(type=TTransportException.NOT_OPEN,
                                message=message)

  def read(self, sz):
    try:
      buff = self.handle.recv(sz)
    except socket.error, e:
      if (e.args[0] == errno.ECONNRESET and
          (sys.platform == 'darwin' or sys.platform.startswith('freebsd'))):
        # freebsd and Mach don't follow POSIX semantic of recv
        # and fail with ECONNRESET if peer performed shutdown.
        # See corresponding comment and code in TSocket::read()
        # in lib/cpp/src/transport/TSocket.cpp.
        self.close()
        # Trigger the check to raise the END_OF_FILE exception below.
        buff = ''
      else:
        raise
    if len(buff) == 0:
      raise TTransportException(type=TTransportException.END_OF_FILE,
                                message='TSocket read 0 bytes')
    return buff

  def write(self, buff):
    if not self.handle:
      raise TTransportException(type=TTransportException.NOT_OPEN,
                                message='Transport not open')
    sent = 0
    have = len(buff)
    while sent < have:
      plus = self.handle.send(buff)
      if plus == 0:
        raise TTransportException(type=TTransportException.END_OF_FILE,
                                  message='TSocket sent 0 bytes')
      sent += plus
      buff = buff[plus:]

  def flush(self):
    pass


class TServerSocket(TSocketBase, TServerTransportBase):
  """Socket implementation of TServerTransport base."""

  def __init__(self, host=None, port=9090, unix_socket=None):
    self.host = host
    self.port = port
    self._unix_socket = unix_socket
    self.handle = None

  def listen(self):
    res0 = self._resolveAddr()
    for res in res0:
      if res[0] is socket.AF_INET6 or res is res0[-1]:
        break

    # We need remove the old unix socket if the file exists and
    # nobody is listening on it.
    if self._unix_socket:
      tmp = socket.socket(res[0], res[1])
      try:
        tmp.connect(res[4])
      except socket.error, err:
        eno, message = err.args
        if eno == errno.ECONNREFUSED:
          os.unlink(res[4])

    self.handle = socket.socket(res[0], res[1])
    self.handle.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    if hasattr(self.handle, 'settimeout'):
      self.handle.settimeout(None)
    self.handle.bind(res[4])
    self.handle.listen(128)

  def accept(self):
    client, addr = self.handle.accept()
    result = TSocket()
    result.setHandle(client)
    return result
